Ignition timing.

[Le singe]

Does anyone know at what rpm the 1100 reaches full advance?
I've hunted through all the manuals,etc,but just the figure in degrees is given.

 

[Le singe]

Steptoe,have you any idea on this one? I need the info for a one-off ignition system.

 

[Haytch]

Found this thread was unanswered ... I am interested also.
Any Info on how to check ignition advance dynamically? (1100gs)
Cheers
H

 

[Arbreacames]

I have no info on dynamic ignition advance, but the following thread on static timing position is interesting.

 

[Haytch]

Good call ...thanks..... but wanted to verify the 'advance' feature of the ignition as this is where the engine is used most.
The flywheel Z mark seems to not be full advance at higher revs?
........and I am interested in the 1100gs ... think 1150's are differant?

 

[Frank Warner]

The advance is not simply related to engine rpm, but also throttle angle .. and possibly engine temperature! So it would not be possible to 'simply' check the advance.

 

[Haytch]

Thanks Frank ... did not realise this. Is the system 'stepped' in blocks through its advance or is it a non-linear adjustment.
Does anyone have any more info on the system, and how do BMW dealers check it?
thanks
H

 

[Le singe]

Haych - this is exactly the information I believed I needed when deciding on the advance curve for the ignition unit I'm using to replace the Motronic set-up with my carb conversion.
I tried to get an idea of the standard advance curve, but it was impossible, as Frank says, the signal from the Hall sensors is intercepted by the Motronic box, which then enters other variables, throttle opening etc, into the equation, and then varys the timing accordingly. Even when strobing under load, the advance seemed to be constantly moving!
Assuming your Hall sensors are problem free, the only way of verifying the advance is working correctly, is to get a BMW dealer to perform a test on the Motronic box.